torture: Make "--dryrun script" output self-sufficient

The scripts produced by kvm.sh's "--dryrun script" argument were intended
for debugging rather than to run, but it is easier to debug if the script
output matches exactly what is run.  This commit therefore makes this
script runnable.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>